Although the livestock wastewater causes severe water pollution, only few people recognize the extent of the pollution. Taking hog wastewater as an example, Taiwan raised at least 10 million heads of hogs which is 0.5 hog raised per person in average, making the highest ratio between hog and population in the world, according to official statistics. The average daily excreta per hog is six times higher than that of human beings, therefore, in case untreated hog wastewater is discharged into rivers, the accumulated pollution will cause serious problems.
To solve said severe pollution problem, the government has made unsparing efforts into the research and development on pollution control measures. However, most of them adopted use methane fermentation techniques. The failure to successfully separate solids from liquids results in high BOD (Biochemical Oxygen Demand) value and SS (Suspended Solids) for normal discharge. Moreover, it requires adding of chemical precipitatant or coagulant to help in sedimentation and condensation, thereby causing secondary pollution. Although said technique claims the byproduct of methane gas, it is impractical to commercialize as the fuel for power generators, vehicles and boilers due to the consideration on cost-effect and the fact that it requires great a investment in additional facilities. Therefore, no matter what incentives the government proposed, owners are hesitate in taking advantage of said techniques and livestock wastewater still poses great threats to our living environment.
Furthermore, the long and overdosed use of chemical fertilizers in agriculture has acidified Taiwan's soil that has not only impaired plants growth, but also caused yield reduction. Most farmers resort to higher dosage to increase output, causing the soil to be further acidified. To avoid such a vicious cycle, the best way is that we should give up chemical fertilizers for more natural organic ones. Excreta in the livestock wastewater is picked up directly by the way of mechanical separation of solid and liquid, which is then delivered outside for traditional piling treatment. However, the excreta produced based on above-mentioned method is unstable in physical and chemical properties, giving out nuisant odors under normal temperature and reducing value benefit, as well as causing great burdens to environmental sanitation.
The inventor has realized the above-mentioned defects in traditional techniques, which can hardly slove the existed livestock wastewater pollution problems, and made a best effort for better methods to turn trash into treasure based on his experiences on environment protection engineering in the field of research and development and success after numerous tests and improvements.